Method of and apparatus for briquetting fine-grained, pulverulent, or dust-fine material



March 11, 194k F. HERGLOTZ 2 4,

" METHOD OF AND APPARATUS FOR BRIQUETTING FINE-GRAINED,

PULVERULENT, 0R DUST-FINE MATERIAL Filed 0ct. 6, 1938 lb venlor f (q n3Alforney UNITED STATES PATENT Franz Herglotz, Karlsbad, CzechoslovakiaApplication October 6, i938, Serial No. 233,546

In Germany August 6, 19%? 9 Ciaiinis.

This invention relates to a method of and apparatus for briquettingfine-grained, pulverulent or dust-fine material.

In briquetting fine-grained, pulverulent or dustfine material it hasbeen found advantageous to compact the material before introducing itinto the briquetting press so as partly to extract from said materialthe air included therein. By this means the weight per unit volume ofthe material to be moulded, and hence the capacity of the briquettingpress with respect to quantity and nature of the briquettes mouldedtherein can be substantially increased. This applies particularly toroller presses, which'consist of a pair of rolls running in oppositedirections, and also to ring roller moulding presses having a rollmounted eccentrically in a rotatable ring and rotating in the samedirection as the latter. In view of the particularly great capacity ofsuch presses for receiving and Working material, it is particularlyimportant to supply to the press per unit period material to be mouldedof uniform density, in quantities which are as large and as uniform aspossible.

According to the present invention, the compacting of the material to bemoulded is effected, by passing said material, before moulding, througha worm conveyor or feeding screw travelling at high speed and dammingthe same by all a resistance, for the purpose of maintaining thecompression of the material produced by the high speed worm conveyorwhich would otherwise be wasted if the material were allowed to passunobstructed out of the worm. The damming of the material to be mouldedis very conveniently regulated by applying theretd an adjustablecounter-pressure.

The degree of compacting of the material to be moulded can be regulatedboth by varying the speed of rotation of the worm and by adjusting thecounter-pressure, or by both measures simultaneously. Practically allvariations in pressure in the material to be moulded are equalised bythe adjustable counter-pressure, thereby ensuring a completely uniformsupply to the briquetting press.

The compacted material may pass either directly or indirectly to theactual moulding. The distance between the worm and the briquettingpress, i. e. between the delivery end of the worm and the press mould,is dependent, per se, upon constructional factors and is not limited bythe invention. In certain circumstances, the casing of the worm may bemade relatively long or the damming of the material to bemoulded may be(ill. m)

maintained by wall friction in a correspondingly long ortapering'tubular conduit.

The invention may be carried out by disposing the high speed worm in,and advantageously at the end of, thepath along which the material to gbe briquetted travels to the press, thus compacting said material Whilefeeding it to the press. To this end, only a small portion of the normalconveying device for the material need generally be in the form of arapidly rotating worm, while feeding screws working at the usual speed,i. e. about 50 to 120 R. P. ML, or similarly acting conveyors can beused in the major portion of said conveying device.

In carrying out the invention, the speed of rotation of the high speedworm may be selected in accordance with the nature ofthe material andthe degree of compacting intended. It has been found that in order toachieve a degree of compacting suitable for the'purposes of the presentinvention, the speed of rotation of the Worm should preferably varyinversely with the degree of fineness of the material to be moulded. Asa rule speeds lying between 300 and 2,500 R. P. M. preferably from 700to 1500 R. P. M... are used.

- Worms having a low pitch have been found to be particularly suitablefor carrying out the invention. The threads of the high-speed worm canbe partly or wholly interrupted or can be partly or wholly replaced .byhelically disposed strips, pins, or similar projections. The density ofthe material is thereby rendered uniform. It is advantageous to useworms of small structural length and to mount such worm only at the endremote from the press.

A particularly advantageous method of carrying out the inventioncomprises continually supplying to the high-speed worm more materialthan the briquetting press will take, continually withdrawing betweenthe press and said worm the excess supplied to the latter and regulatingthe counter-pressure when withdrawing -the excess, i. e. providing thecounter-pressure regulator in the member through which the excess iswithdrawn.

, In order to enable the invention to be more readily understood,reference is made to the accompanying drawing which illustratesdiagrammatically and by way of example various emv bodiments ofapparatusfor carrying the invention into practical effect, and in which:

Fig. 1 shows a compacting device and the briquettlng press, partly insection and partly in plan; and

Figs. 2 and 3 illustrate schematically two fur-' ther embodiments;

In said drawing; like parts are denoted by like characters of reference.

Fig. 1 illustrates the charging of a roller press I by means of ahigh-speed worm 2, which takes the material to be briquetted from asupply conduit 3 and conveys the same into the tree portion of the workcasing 4, from which the compacted material passes by way of a partlyclosed filling member 5 between the rollers of the press. If desired,the worm may also occupy the entire length of the worm casing. Thecasing has a branch pipe connection 6 which is closed by a valve disc 8loaded by an adjustable spring I.

As soon as the pressure of the material dammed in the part 4, exceedsthe counter-pressure of the spring I, the valve 8 opens and allowsexcess material to be passed out into the chamber 9 from whence it canbe withdrawn through a pipe ill, to be conveniently passed back to thesupply pipe 3. The valve 8 may be loaded by a weight, or by pneumatic orhydraulic pressure, or by electromagnetic or similar means, instead ofby spring pressure.

In Figs. 2 and 3, only the conduit 4 for feedin to the press the alreadycompacted material to be moulded and the press I itself are indicated inpurely schematic form.

The worm casing 4 has a branch cylinder ll in which latter a piston I2,loaded by a spring 13, is adapted to move up and down under thepressure. As soon as thepressure of the dammed material to be briquettedrises, the piston I2 is raised under the load or the spring it untilthis load is in equilibrium with the pressure in the part 4. In this wayvariations in pressure occurring in the material to be-briquettedareautomatically equalised by the loaded piston.- The.

piston may also be loaded in any other suitable manner, as describedwith reference to the valve 8 shown in Fig. 1.

The bucket wheel I4 shown in Fig. 3 enables any excess supplied to theworm to be constantly withdrawn while maintaining the damming pressure.

The hereindescribed method and apparatus have been found particularlysuitable for the production of compact and solid briquettes from coalcomminuted to dust fineness. Thus for example, it has been foundpossible by means of the invention, using a worm having a speed of 1000R, P. M., to increase the weight per unit volume of pit-coal, dried to amoisture content of 1% and comminuted to a maximum grain size of 0.2mm., from 0.4 to 0.7 gram, per cubic centimetre, and thereafter tocompress said coal, without the addition of binders, into compact andsolid briquettes, in a ring roller moulding press.

I claim:

1. In a method of briquetting fine-grained pulverulent material, thesteps which comprise conveying saidpulverulent material to a briquettingoperation at a greater rate than that at which the briquetting operationtakes place, whilst damming said material by a resistance during saidconveying operation in order to compact the same, withdrawing excess ofcompacted material and thereupon briquetting the remainder of thecompacted material.

2. An apparatus ior briquetting fine-grained pulverulent material,comprising a casing having an inlet and outlet, 3, high speed wormrotating in said casing, a counter-pressure regulator beyond thedelivery end of said worm, and a briquetting press located at the outletof said casing.

3. An apparatus for briquetting fine-grained pulverulent material,comprising a casing having an inlet and outlet, a high speed wormrotating in said casing, a loaded valve serving as counter-pressureregulator beyond the delivery end of said worm and a briquetting presslocated at the outlet of said casing.

4. In a method of briquetting fine-grained pulverulent material, thesteps which comprise rapidly agitating whilst simultaneously conveyingsaid pulverulent material to a briquetting operation, damming saidmaterial on its way to the briquetting operation by a resistance inorder to increase the bulk density thereof and thereupon briquettingsaid material.

5. In a method of briquetting fine-grained pulverulent material, thesteps which comprise rapidly agitating whilst simultaneously conveyingsaid pulverulent material to a briquetting operation, adjusting thedegree of agitation and the rate of conveyance of said material, dammingsaid material on its way to the briquetting operation by a resistance inorder to increase the bulk density thereof and thereupon briquettingsaid material.

6. In a method of briquetting fine-grained pulverulent material. thesteps which comprise rap-' idly agitating whilst simultaneouslyconveying said pulverulent material to a briquetting operation, at agreater rate than that at which said briquetting operation takes place,damming said material onits way to the briquetting operation, by aresistance in order to increase the bulk density thereof, withdrawingexcess of compacted material and briquetting the remainder of thecompacted material.

7. An apparatus for briquetting fine-grained pulverulent material,comprising a casing having an inlet and outlet, a high speed wormrotating in said casing. a counter-pressure regulator associated withsaid casing and a briquetting press located at the outlet of saidcasing.

8. An apparatus for briquetting fine-grained pulverulent material,comprising a casing having an inlet and outlet, a high speed wormrotatin in said casing, a loaded valve serving as counter-pressureregulator associated with said casing and a briquetting press located atthe outlet of said casing.

9. An apparatus for briquetting fine-grained pulverulent material,comprising a casing having an inlet and outlet, ahigh speed wormrotating in said casing, a chamber opening from said casing beyond thedelivery end of said worm, an outlet in said chamber, a counter-pressureregulator controlling the pressure of said material in said chamber, anda briquetting press located at the outlet of said casing. I

FRANZ HERGLOTZ.

